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omap-pcm.c

/*
 * omap-pcm.c  --  ALSA PCM interface for the OMAP SoC
 *
 * Copyright (C) 2008 Nokia Corporation
 *
 * Contact: Jarkko Nikula <jarkko.nikula@nokia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/dma-mapping.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <asm/arch/dma.h>
#include "omap-pcm.h"

static const struct snd_pcm_hardware omap_pcm_hardware = {
      .info             = SNDRV_PCM_INFO_MMAP |
                          SNDRV_PCM_INFO_MMAP_VALID |
                          SNDRV_PCM_INFO_INTERLEAVED |
                          SNDRV_PCM_INFO_PAUSE |
                          SNDRV_PCM_INFO_RESUME,
      .formats          = SNDRV_PCM_FMTBIT_S16_LE,
      .period_bytes_min = 32,
      .period_bytes_max = 64 * 1024,
      .periods_min            = 2,
      .periods_max            = 255,
      .buffer_bytes_max = 128 * 1024,
};

struct omap_runtime_data {
      spinlock_t              lock;
      struct omap_pcm_dma_data      *dma_data;
      int                     dma_ch;
      int                     period_index;
};

static void omap_pcm_dma_irq(int ch, u16 stat, void *data)
{
      struct snd_pcm_substream *substream = data;
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct omap_runtime_data *prtd = runtime->private_data;
      unsigned long flags;

      if (cpu_is_omap1510()) {
            /*
             * OMAP1510 doesn't support DMA chaining so have to restart
             * the transfer after all periods are transferred
             */
            spin_lock_irqsave(&prtd->lock, flags);
            if (prtd->period_index >= 0) {
                  if (++prtd->period_index == runtime->periods) {
                        prtd->period_index = 0;
                        omap_start_dma(prtd->dma_ch);
                  }
            }
            spin_unlock_irqrestore(&prtd->lock, flags);
      }

      snd_pcm_period_elapsed(substream);
}

/* this may get called several times by oss emulation */
static int omap_pcm_hw_params(struct snd_pcm_substream *substream,
                        struct snd_pcm_hw_params *params)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct snd_soc_pcm_runtime *rtd = substream->private_data;
      struct omap_runtime_data *prtd = runtime->private_data;
      struct omap_pcm_dma_data *dma_data = rtd->dai->cpu_dai->dma_data;
      int err = 0;

      if (!dma_data)
            return -ENODEV;

      snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
      runtime->dma_bytes = params_buffer_bytes(params);

      if (prtd->dma_data)
            return 0;
      prtd->dma_data = dma_data;
      err = omap_request_dma(dma_data->dma_req, dma_data->name,
                         omap_pcm_dma_irq, substream, &prtd->dma_ch);
      if (!cpu_is_omap1510()) {
            /*
             * Link channel with itself so DMA doesn't need any
             * reprogramming while looping the buffer
             */
            omap_dma_link_lch(prtd->dma_ch, prtd->dma_ch);
      }

      return err;
}

static int omap_pcm_hw_free(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct omap_runtime_data *prtd = runtime->private_data;

      if (prtd->dma_data == NULL)
            return 0;

      if (!cpu_is_omap1510())
            omap_dma_unlink_lch(prtd->dma_ch, prtd->dma_ch);
      omap_free_dma(prtd->dma_ch);
      prtd->dma_data = NULL;

      snd_pcm_set_runtime_buffer(substream, NULL);

      return 0;
}

static int omap_pcm_prepare(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct omap_runtime_data *prtd = runtime->private_data;
      struct omap_pcm_dma_data *dma_data = prtd->dma_data;
      struct omap_dma_channel_params dma_params;

      memset(&dma_params, 0, sizeof(dma_params));
      /*
       * Note: Regardless of interface data formats supported by OMAP McBSP
       * or EAC blocks, internal representation is always fixed 16-bit/sample
       */
      dma_params.data_type                = OMAP_DMA_DATA_TYPE_S16;
      dma_params.trigger                  = dma_data->dma_req;
      dma_params.sync_mode                = OMAP_DMA_SYNC_ELEMENT;
      if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
            dma_params.src_amode          = OMAP_DMA_AMODE_POST_INC;
            dma_params.dst_amode          = OMAP_DMA_AMODE_CONSTANT;
            dma_params.src_or_dst_synch   = OMAP_DMA_DST_SYNC;
            dma_params.src_start          = runtime->dma_addr;
            dma_params.dst_start          = dma_data->port_addr;
      } else {
            dma_params.src_amode          = OMAP_DMA_AMODE_CONSTANT;
            dma_params.dst_amode          = OMAP_DMA_AMODE_POST_INC;
            dma_params.src_or_dst_synch   = OMAP_DMA_SRC_SYNC;
            dma_params.src_start          = dma_data->port_addr;
            dma_params.dst_start          = runtime->dma_addr;
      }
      /*
       * Set DMA transfer frame size equal to ALSA period size and frame
       * count as no. of ALSA periods. Then with DMA frame interrupt enabled,
       * we can transfer the whole ALSA buffer with single DMA transfer but
       * still can get an interrupt at each period bounary
       */
      dma_params.elem_count   = snd_pcm_lib_period_bytes(substream) / 2;
      dma_params.frame_count  = runtime->periods;
      omap_set_dma_params(prtd->dma_ch, &dma_params);

      omap_enable_dma_irq(prtd->dma_ch, OMAP_DMA_FRAME_IRQ);

      return 0;
}

static int omap_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct omap_runtime_data *prtd = runtime->private_data;
      int ret = 0;

      spin_lock_irq(&prtd->lock);
      switch (cmd) {
      case SNDRV_PCM_TRIGGER_START:
      case SNDRV_PCM_TRIGGER_RESUME:
      case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
            prtd->period_index = 0;
            omap_start_dma(prtd->dma_ch);
            break;

      case SNDRV_PCM_TRIGGER_STOP:
      case SNDRV_PCM_TRIGGER_SUSPEND:
      case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
            prtd->period_index = -1;
            omap_stop_dma(prtd->dma_ch);
            break;
      default:
            ret = -EINVAL;
      }
      spin_unlock_irq(&prtd->lock);

      return ret;
}

static snd_pcm_uframes_t omap_pcm_pointer(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct omap_runtime_data *prtd = runtime->private_data;
      dma_addr_t ptr;
      snd_pcm_uframes_t offset;

      if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
            ptr = omap_get_dma_src_pos(prtd->dma_ch);
      else
            ptr = omap_get_dma_dst_pos(prtd->dma_ch);

      offset = bytes_to_frames(runtime, ptr - runtime->dma_addr);
      if (offset >= runtime->buffer_size)
            offset = 0;

      return offset;
}

static int omap_pcm_open(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct omap_runtime_data *prtd;
      int ret;

      snd_soc_set_runtime_hwparams(substream, &omap_pcm_hardware);

      /* Ensure that buffer size is a multiple of period size */
      ret = snd_pcm_hw_constraint_integer(runtime,
                                  SNDRV_PCM_HW_PARAM_PERIODS);
      if (ret < 0)
            goto out;

      prtd = kzalloc(sizeof(prtd), GFP_KERNEL);
      if (prtd == NULL) {
            ret = -ENOMEM;
            goto out;
      }
      spin_lock_init(&prtd->lock);
      runtime->private_data = prtd;

out:
      return ret;
}

static int omap_pcm_close(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;

      kfree(runtime->private_data);
      return 0;
}

static int omap_pcm_mmap(struct snd_pcm_substream *substream,
      struct vm_area_struct *vma)
{
      struct snd_pcm_runtime *runtime = substream->runtime;

      return dma_mmap_writecombine(substream->pcm->card->dev, vma,
                             runtime->dma_area,
                             runtime->dma_addr,
                             runtime->dma_bytes);
}

struct snd_pcm_ops omap_pcm_ops = {
      .open       = omap_pcm_open,
      .close            = omap_pcm_close,
      .ioctl            = snd_pcm_lib_ioctl,
      .hw_params  = omap_pcm_hw_params,
      .hw_free    = omap_pcm_hw_free,
      .prepare    = omap_pcm_prepare,
      .trigger    = omap_pcm_trigger,
      .pointer    = omap_pcm_pointer,
      .mmap       = omap_pcm_mmap,
};

static u64 omap_pcm_dmamask = DMA_BIT_MASK(32);

static int omap_pcm_preallocate_dma_buffer(struct snd_pcm *pcm,
      int stream)
{
      struct snd_pcm_substream *substream = pcm->streams[stream].substream;
      struct snd_dma_buffer *buf = &substream->dma_buffer;
      size_t size = omap_pcm_hardware.buffer_bytes_max;

      buf->dev.type = SNDRV_DMA_TYPE_DEV;
      buf->dev.dev = pcm->card->dev;
      buf->private_data = NULL;
      buf->area = dma_alloc_writecombine(pcm->card->dev, size,
                                 &buf->addr, GFP_KERNEL);
      if (!buf->area)
            return -ENOMEM;

      buf->bytes = size;
      return 0;
}

static void omap_pcm_free_dma_buffers(struct snd_pcm *pcm)
{
      struct snd_pcm_substream *substream;
      struct snd_dma_buffer *buf;
      int stream;

      for (stream = 0; stream < 2; stream++) {
            substream = pcm->streams[stream].substream;
            if (!substream)
                  continue;

            buf = &substream->dma_buffer;
            if (!buf->area)
                  continue;

            dma_free_writecombine(pcm->card->dev, buf->bytes,
                              buf->area, buf->addr);
            buf->area = NULL;
      }
}

int omap_pcm_new(struct snd_card *card, struct snd_soc_dai *dai,
             struct snd_pcm *pcm)
{
      int ret = 0;

      if (!card->dev->dma_mask)
            card->dev->dma_mask = &omap_pcm_dmamask;
      if (!card->dev->coherent_dma_mask)
            card->dev->coherent_dma_mask = DMA_32BIT_MASK;

      if (dai->playback.channels_min) {
            ret = omap_pcm_preallocate_dma_buffer(pcm,
                  SNDRV_PCM_STREAM_PLAYBACK);
            if (ret)
                  goto out;
      }

      if (dai->capture.channels_min) {
            ret = omap_pcm_preallocate_dma_buffer(pcm,
                  SNDRV_PCM_STREAM_CAPTURE);
            if (ret)
                  goto out;
      }

out:
      return ret;
}

struct snd_soc_platform omap_soc_platform = {
      .name       = "omap-pcm-audio",
      .pcm_ops    = &omap_pcm_ops,
      .pcm_new    = omap_pcm_new,
      .pcm_free   = omap_pcm_free_dma_buffers,
};
EXPORT_SYMBOL_GPL(omap_soc_platform);

MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@nokia.com>");
MODULE_DESCRIPTION("OMAP PCM DMA module");
MODULE_LICENSE("GPL");

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